Imprinting mold and method for making lens array

ABSTRACT

An exemplary method for making a lens array is as follows. An imprinting mold and a substrate are provided. A blob of molding material is applied on each molding section of the substrate. The first alignment marks, and the second alignment mark of the imprinting mold are aligned with the fourth alignment marks, and the third alignment mark of one of the imprinting regions, respectively. The imprinting mold is pressed on the molding material on the imprinting region. The pressed portions of the imprinting region are solidified to obtain lenses in the imprinting region. The imprinting mold is pressed on another one of the imprinting region, and the imprinting mold is removed. This process is repeated for each other imprinting region. Thus, a lens array is obtained.

BACKGROUND

1. Technical Field

The present disclosure relates to an imprinting mold that includes alignment marks, and to a method for making a lens array using such kind of imprinting mold.

2. Description of Related Art

Imprinting technology is a simple process with low cost, high throughput and high resolution. Imprinting technology is widely used for making a lens array in a wafer lens package (WLP) process.

In an imprinting process involving a large substrate, a large size imprinting mold is usually employed to produce a lens array on the substrate. However, the large size imprinting mold may be very expensive to make due to the need for high precision. Furthermore, it may be unduly time-consuming to manufacture the large size imprinting mold.

Therefore, an imprinting mold and a method for making a lens array which can overcome the above mentioned problems are desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an isometric view of an imprinting mold including a plurality of first alignment marks and a plurality of second alignment marks according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the imprinting mold of FIG. 1, taken along line II-II thereof.

FIG. 3 is an isometric view of a substrate including a plurality of third alignment marks and a plurality of fourth alignment marks according to an exemplary embodiment of the present invention.

FIG. 4 is a cross-sectional view of the substrate of FIG. 3, taken along line IV-IV thereof.

FIG. 5 is similar to FIG. 4, but showing the substrate with a blob of molding material applied to each of molding sections thereof.

FIG. 6 shows the imprinting mold of FIG. 2 and the substrate of FIG. 5, wherein the first alignment marks and the second alignment marks of the imprinting mold are aligned with the fourth alignment marks and the third alignment marks of one of imprinting regions of the substrate, respectively.

FIG. 7 is similar to FIG. 6, but showing the imprinting mold pressed on the molding material on the imprinting region, and the pressed portions of the molding material being solidified with ultraviolet (UV) light.

FIG. 8 is similar to FIG. 7, but showing the imprinting mold pressed on molding material on another one of the imprinting regions of the substrate, and the pressed portions of the molding material being solidified with UV light.

FIG. 9 is similar to FIG. 8, but with the imprinting mold having been removed, thus showing a lens array formed on the substrate.

DETAILED DESCRIPTION

Various embodiments will now be described in detail below with reference to the drawings.

Referring to FIG. 9, an exemplary method for making a lens array 400 is described in detail as follows:

Referring to FIGS. 1 and 2, an imprinting mold 100 is provided. The imprinting mold 100 includes a molding surface 110. A plurality of microstructures 120 are defined in the molding surface 110. The microstructures 120 are configured for molding the lens array 400. In the present embodiment, the microstructures 120 are recesses defined in the molding surface 110. It can be understood that in alternative embodiments, the microstructures 120 can be protrusions protruding from the molding surface 110. In the present embodiment, a surface of each microstructure 120 is aspheric. It can be understood that in alternative embodiments, the surface of each microstructure 120 can be spherical.

A plurality of first alignment marks 130 are formed on the molding surface 110. In the present embodiment, the first alignment marks 130 are protrusions protruding from the molding surface 110. It can be understood that in alternative embodiments, the first alignment marks 130 can be recesses defined in the molding surface 110. Two first alignment marks 130 are adjacent to each microstructure 120. Each of the first alignment marks 130 can be, for example, cross-shaped, T-shaped, I-shaped, F-shaped or E-shaped. In the present embodiment, each of the first alignment marks 130 is cross-shaped. In the present embodiment, two first alignment marks 130 are arranged symmetrically opposite each other across the center of the corresponding microstructure 120, and are spaced apart from the microstructure 120. It can be understood that the number and the arrangement of the first alignment marks 130 can be varied according to the requirements of practical applications.

Two second alignment marks 140 are formed at two opposite peripheries of the molding surface 110. In the present embodiment, the second alignment marks 140 are protrusions protruding from the molding surface 110. In alternative embodiments, the second alignment marks 140 can be recesses defined in the molding surface 110. Each of the second alignment marks 140 can be, for example, cross-shaped, T-shaped, I-shaped, F-shaped or E-shaped. In the present embodiment, each of the second alignment marks 140 is cross-shaped. In the present embodiment, the two second alignment marks 140 are arranged along an imaginary horizontal line, at two opposite ends of the molding surface 110, respectively. It can be understood that the number and the arrangement of the second alignment marks 140 can be varied according to the requirements of practical applications. In the present embodiment, each of the second alignment marks 140 has a larger size than each of the first alignment marks 130.

Referring to FIGS. 3 and 4, a substrate 200 is provided. The substrate 200 includes a surface 210. The surface 210 is divided into four imprinting regions 220 (demarcated by broken lines in FIG. 3). It can be understood that the number of imprinting regions 220 is not limited to four. In alternative embodiments, the number of imprinting regions 220 can be less than four or more than four.

Two third alignment marks 230 are formed at two opposite peripheries of each imprinting region 220. The third alignment marks 230 of each imprinting region 220 are positioned corresponding to the second alignment marks 140 of the imprinting mold 100. In the present embodiment, the third alignment marks 230 are recesses defined in the surface 210. In the present embodiment, the third alignment marks 230 have the same shape as the second alignment marks 140; that is, the third alignment marks 230 are cross-shaped. It can be understood that the number and the arrangement of the third alignment marks 230 can be varied according to the requirements of practical applications.

Each of the imprinting regions 220 is divided into a plurality of molding sections 222 (one of which is demarcated by broken lines in FIG. 3). Two fourth alignment marks 240 are formed on each of the molding sections 222. The two fourth alignment marks 240 of each molding section 222 are positioned corresponding to the two first alignment marks 130 adjacent a respective one of the microstructures 120 of the imprinting mold 100. In the present embodiment, the fourth alignment marks 240 are recesses defined in the surface 210. In the present embodiment, the fourth alignment marks 240 have the same shape as the first alignment marks 130; that is, the fourth alignment marks 240 are cross-shaped. It can be understood that the number and the arrangement of the fourth alignment marks 240 can be varied according to the requirements of practical applications. In the present embodiment, each of the third alignment marks 230 has a larger size than each of the fourth alignment marks 240.

In one embodiment, the first alignment marks 130, the second alignment marks 140, the third alignment marks 230, and the fourth alignment marks 240 are all formed by a photolithographic process.

Referring to FIG. 5, a blob of molding material 300 is applied to each of the molding sections 222. The molding material 300 can be, for example, epoxy resin, acrylate-based resin, polyurethane, or polymerized siloxane.

Referring to FIG. 6, the first alignment marks 130 and the second alignment marks 140 of the imprinting mold 100 are aligned with the fourth alignment marks 240 and the third alignment marks 230 of one of the imprinting regions 220, respectively.

Referring to FIG. 7, the imprinting mold 100 is pressed on the molding material 300 on the imprinting region 220, and pressed portions of the molding material 300 are solidified with ultraviolet (UV) light.

Referring to FIG. 8, after the pressed portions of the molding material 300 are solidified, the imprinting mold 100 is removed, thereby exposing a plurality of lenses 260 formed on the imprinting region 220. Subsequently, the imprinting mold 100 is pressed on molding material 300 on another one of the imprinting regions 220. Then the pressed portions of the molding material 300 are solidified, and the imprinting mold 100 is removed. This process is repeated for each other imprinting region 220. Thus, a lens array 400 with a full plurality of all the lenses 260 is obtained, as shown in FIG. 9.

It is to be noted that, in the process of forming a plurality of lenses 260 on each imprinting region 220, the UV light should be controlled to avoid solidifying unpressed portions of molding material 300 on other imprinting regions 220 not yet processed. It can be understood that in other embodiments, the molding material 300 of a next imprinting region 220 to be processed can be applied only after solidifying of the molding material 300 of the imprinting region 220 currently being processed.

Because the second alignment marks 140 align with the third alignment marks 230, the imprinting mold 100 can be aligned with each of the imprinting regions 220. At the same time, because the first alignment marks 130 align with the fourth alignment marks 240, each molding section 222 of the imprinting region 220 can be aligned with each of the corresponding microstructures 120 of the imprinting mold 100. Therefore, the precision of the lens array 400 can be improved.

While certain embodiments have been described and exemplified above, various other embodiments from the foregoing disclosure will be apparent to those skilled in the art. The present invention is not limited to the particular embodiments described and exemplified, but is capable of considerable variation and modification without departure from the scope and spirit of the appended claims. 

1. An imprinting mold comprising a molding surface, the molding surface comprising: a plurality of microstructures defined thereat; a plurality of first alignment marks adjacent each of the microstructures; and a second alignment mark.
 2. The imprinting mold of claim 1, wherein the second alignment mark is formed at a periphery of the molding surface.
 3. The imprinting mold of claim 1, wherein the first alignment marks are protrusions protruding from the molding surface.
 4. The imprinting mold of claim 1, wherein the first alignment marks are recesses defined in the molding surface.
 5. The imprinting mold of claim 1, wherein the second alignment mark is a protrusion protruding from the molding surface.
 6. The imprinting mold of claim 1, wherein the second alignment mark is a recess defined in the molding surface.
 7. The imprinting mold of claim 1, wherein the second alignment mark has a larger size than that of each of the first alignment marks.
 8. The imprinting mold of claim 1, wherein two of the plurality of first alignment marks are arranged symmetrically opposite each other across the center of a corresponding one of the microstructures, and are spaced apart from the microstructure.
 9. A method for making a lens array, the method comprising: (1) providing an imprinting mold, the imprinting mold comprising a molding surface, the molding surface comprising a plurality of microstructures defined thereat, a plurality of first alignment marks adjacent each of the microstructures, and a second alignment mark; (2) providing a substrate, the substrate comprising a surface, the surface being divided into a plurality of imprinting regions, a third alignment mark corresponding to the second alignment mark being formed in each of the imprinting regions, each of the imprinting regions being divided into a plurality of molding sections, a plurality of fourth alignment marks being formed in each of the molding sections, the fourth alignment marks corresponding to the first alignment marks; (3) applying a blob of molding material on each of the molding sections of at least one of the imprinting regions; (4) aligning the first alignment marks and the second alignment mark of the imprinting mold with the fourth alignment marks and the third alignment mark of one imprinting region which has the molding material applied thereon, respectively; (5) pressing the imprinting mold on the molding material on the imprinting region; (6) solidifying the pressed portions of molding material on the imprinting region to obtain a plurality of lenses on the imprinting region; and (7) repeating (3) if and as needed and repeating (4) through (6) as needed to obtain a lens array comprising a plurality of the lenses.
 10. The method of claim 9, wherein the molding material is selected from the group consisting of epoxy resin, acrylate-based resin, polyurethane, and polymerized siloxane.
 11. The method of claim 9, wherein the pressed portions are solidified by ultraviolet (UV) light irradiation.
 12. The method of claim 9, wherein the third alignment mark is a protrusion protruding from the surface of the substrate.
 13. The method of claim 9, wherein the third alignment mark is a recess defined in the surface of the substrate.
 14. The method of claim 9, wherein the fourth alignment marks are protrusions protruding from the surface of the substrate.
 15. The method of claim 9, wherein the fourth alignment marks are recesses defined in the surface of the substrate.
 16. A method for making a lens array, the method comprising: (1) providing an imprinting mold, the imprinting mold comprising a molding surface, the molding surface comprising a plurality of microstructures defined thereat, a plurality of first alignment marks adjacent each of the microstructures, and a second alignment mark, the second alignment mark being formed at a periphery of the molding surface; (2) providing a substrate, the substrate comprising a surface, the surface being divided into a plurality of imprinting regions, a third alignment mark corresponding to the second alignment mark being formed in each of the imprinting regions, each of the imprinting regions being divided into a plurality of molding sections, a plurality of fourth alignment marks being formed in each of the molding sections, the fourth alignment marks corresponding to the first alignment marks; (3) applying a blob of molding material on each of the molding sections of at least one of the imprinting regions; (4) aligning the first alignment marks and the second alignment mark of the imprinting mold with the fourth alignment marks and the third alignment mark of one imprinting region which has the molding material applied thereon, respectively; (5) pressing the imprinting mold on the molding material on the imprinting region; (6) solidifying the pressed portions of molding material on the imprinting region to obtain a plurality of lenses on the imprinting region; and (7) selectively repeating any one or more of (3) through (6) if and as required to obtain a lens array comprising a plurality of the lenses. 